A method of equalising optical losses, at a required operating wavelength, in waveguide sections in an optoelectronic device comprising a first semiconductor waveguide section and a second semiconductor waveguide section, the method comprising determining (1301) a first optical loss through the first waveguide section for a signal with the required operating wavelength, determining (1302) a second optical loss through the second waveguide section for the signal, determining (1303) a loss difference between the first optical loss and the second optical loss, determining (1304) a first bias voltage based on the loss difference and the operating wavelength, such that the loss difference is reduced, and applying (1305) the bias voltage to the first waveguide section.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
Negative bias to improve phase noise A method of operating an optoelectronic device comprising an optical waveguide section, the optical waveguide section comprising a semiconductor core, the method comprising the steps of determining (401) a range for a negative bias voltage for the waveguide section for which an optical loss of the core is lower than an optical loss at zero bias for an operating wavelength range of the device, selecting (402) a bias voltage within the range and applying (403) the selected bias voltage to the waveguide section.
H01S 5/026 - Monolithically integrated components, e.g. waveguides, monitoring photo-detectors or drivers
G02F 1/025 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction in an optical waveguide structure
G02B 6/10 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
A waveguide structure for use in a balanced push-pull Mach Zehnder modulator. The waveguide structure comprises a plurality of layers. The layers comprise, in order: an insulating or semi-insulating substrate; an lower cladding layer; an waveguide core layer; and an upper cladding layer. The lower cladding layer, waveguide core layer, and upper cladding layer are etched to form: a signal waveguide and a ground waveguide, which are connected via the lower cladding layer; and a signal line and a ground line, each located adjacent to the respective waveguide, and each connected to the respective waveguide via one or more respective resistive structures connected in the plane of the lower cladding layer.
An optical filter comprising a first lens, and first and second optical elements. The first lens has an optical axis, configured to focus beams propagating parallel to the optical axis at a focal point. The first optical element has a first semi-reflective surface, the first semi-reflective surface being curved and having a first radius of curvature around a first centre of curvature on the optical axis. The second optical element has a second semi- reflective surface. The first radius of curvature is between 1 and 10,000 times the distance between the first semi reflective surface and the focal point along the optical axis. The first and second semi-reflective surfaces are arranged to form a resonator. The first lens and the first and second semi-reflective surfaces are arranged along the optical axis such that light is transmittable along an optical path through the lens and the resonator. The optical filter further comprises one or more expansion elements located outside of the optical path, and arranged such that expansion of the expansion elements causes relative movement of the first and second semi-reflective surfaces.
G02B 6/293 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
5.
APPARATUS FOR MONITORING THE OUTPUT OF AN OPTICAL SYSTEM
Apparatus for monitoring the output of an optical system. The apparatus comprises first and second fibre optic sections, a reflective coating, and a detector. The first fibre optic section has a first cladding and a first core, and is configured to receive light from the optical system at one end and has at the other end a first angled, polished face. The second fibre optic section has a second cladding and a second core, and has at one end a second angled, polished face. The first and second fibre optic sections are arranged such that the first and second angled, polished faces are substantially parallel and adjacent and the first and second cores are substantially aligned. The reflective coating is applied to the first or second angled, polished face, and is configured to reflect a portion of light transmitted through the first core. The detector is arranged to receive the reflected light. An alternative apparatus for monitoring the output of an optical system is also disclosed, the apparatus comprising a beam splitter, a lens, a fibre optic stub having a core and a cladding, and a detector, wherein the beam splitter is configured to receive light from the output of the optical system and has first and second outputs, the first output being configured to pass light to a fibre optic cable. The lens is configured to focus light from the second beam splitter output into the core of the fibre optic stub, and the detector is configured to receive light from the fibre optic stub.
According to a first aspect of the present invention, there is provided an optical filter. The optical filter comprises first and second optical elements, and one or more expansion elements. The first and second optical elements are arranged along a common axis, each terminates in a flat surface perpendicular to the axis. The flat surfaces are separated by a gap having a width d, such that the flat surfaces form a Fabry-Perot etalon and light is transmittable along an optical path through the elements and the etalon. The one or more expansion elements are connected to the optical elements, located outside the optical path and extend parallel to the axis with a length greater than the width of the gap. The expansion elements comprise a material having a linear thermal coefficient of expansion different to that of the optical elements such that a difference in expansion of the expansion elements and the optical elements causes relative movement of the flat surfaces along the axis resulting in a change in the width of the gap.
A method of providing electrical isolation between subsections in a waveguide structure for a photonic integrated device, the structure comprising a substrate, a buffer layer and a core layer, the buffer layer being located between the substrate and the core and comprising a dopant of a first type, the first type being either n-type or p-type, the method comprising the steps of prior to adding any layer to a side of the core layer opposite to the buffer layer: selecting at least one area to be an electrical isolation region, applying a dielectric mask to a surface of the core layer opposite to the buffer layer, with a window in the mask exposing an area of the surface corresponding to the selected electrical isolation region, implementing diffusion of a dopant of a second type, the second type being of opposite polarity to the first type, and allowing the dopant of the second type to penetrate to the substrate to form a blocking junction.
G02B 6/42 - Coupling light guides with opto-electronic elements
G02B 6/43 - Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
H01L 21/76 - Making of isolation regions between components
There is described an RF waveguide array. The array comprises a substrate comprising a plurality of optical waveguides, each waveguide being elongate in a first direction. An electrical RF transmission line array is located on a face of the substrate and comprises a plurality of signal electrodes and a plurality of ground electrodes, each electrode extending in the first direction. Each signal electrode is positioned to provide a signal to two respective waveguides. The ground electrodes include at least one intermediate ground electrode positioned between each pair of signal electrodes. Each intermediate ground electrode includes a portion extending into the substrate.
G02F 1/03 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels or Kerr effect
G02F 1/035 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels or Kerr effect in an optical waveguide structure
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
There is disclosed a DBR laser and a method of use. The DBR laser comprises a phase section in a cavity of the DBR laser and configured to adjust an optical path length of the cavity. A DBR section comprises a frequency tuning system configured to adjust a Bragg frequency of the DBR section. A detector is configured to detect laser light transmitted through the DBR section. A controller is configured: to cause the phase section to apply a dither to the optical path length of the cavity or cause the frequency tuning system to apply a dither to the Bragg frequency of the DBR section; to use the detector to monitor intensity of light transmitted from the laser cavity via the DBR section during application of the dither; to determine a deviation from longitudinal mode centre operation on the basis of the monitored intensity; and to cause the frequency tuning system to adjust the Bragg frequency of the DBR section in order to reduce said deviation, or cause the phase section to adjust the optical path length of the cavity in order to reduce said deviation.
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
In accordance with one aspect of the present application there is provided a DBR, laser. The DBR laser comprises a phase section in a cavity of the DBR laser configured to adjust an optical path length of the cavity. The laser also comprises a DBR section comprising a frequency tuning system, the frequency tuning system comprising a resistance heater configured to apply heat to a grating of the DBR section in order to adjust a Bragg frequency of the DBR section. A detector is configured to detect laser light transmitted through the DBR section. A controller is configured: to cause the phase section to apply a dither to the optical path length of the cavity or cause the frequency tuning system to apply a dither to the Bragg frequency of the DBR section; to use the detector to monitor intensity of light transmitted from the laser cavity via the DBR section during application of the dither; to determine a deviation from longitudinal mode centre operation on the basis of the monitored intensity; to cause the phase section to adjust the optical path length of the cavity in order to reduce said deviation; to determine an output frequency of the DBR laser on the basis of a resistance of the resistance heater; and to control the output frequency of the DBR laser by controlling power to the resistance heater.
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
A waveguide structure including a waveguide having a thermally controllable section, and a method of manufacturing the structure. The waveguide structure comprises a plurality of layers. The layers comprise, in order: a substrate (306), a sacrificial layer (305), a lower cladding layer (303), a waveguide core layer (302), and an upper cladding layer (301). The lower cladding layer, waveguide core layer, and upper cladding layer form the waveguide, the waveguide has a waveguide core. The waveguide structure has a continuous via (307) passing through the upper cladding layer, waveguide core layer, and lower cladding layer and running parallel to the waveguide ridge (304) along substantially the whole length of the thermally controllable section. The waveguide structure also has a thermally insulating region (308) in the sacrificial layer extending at least from the via to beyond the waveguide ridge along the whole length of the thermally controllable section. The sacrificial layer comprises a sacrificial material outside of the thermally insulating region, and a thermally insulating gap (308) or thermally insulating material separating the lower cladding layer and substrate inside the thermally insulating region. The structure is manufactured by providing a wet etch to the sacrificial layer through the via in order to remove material from at least the thermally insulating region.
H01S 5/06 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
H01S 5/20 - Structure or shape of the semiconductor body to guide the optical wave
G02F 1/01 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour
H01S 5/32 - Structure or shape of the active regionMaterials used for the active region comprising PN junctions, e.g. hetero- or double- hetero-structures
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
There is described an interferometer for use in an optical locker. The interferometer comprises at least two transparent materials having different thermal path length sensitivities. The interferometer is configured such that an input beam is split by the interferometer into first and second intermediate beams, which recombine to form an output beam, the first and second intermediate beams travelling along respective first and second intermediate beam paths which do not overlap. At least one of the intermediate beam paths passes through at least two of the transparent materials. A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature.
A radio frequency, RF, waveguide array. The array comprises a substrate and an electrical RF transmission line array. The substrate comprises a plurality of optical waveguides, each waveguide being elongate in a first direction. The electrical RF transmission line array is located on a face of the substrate and comprises a plurality of RF transmission lines. Each transmission line comprises a signal electrode and at least two ground electrodes located on either side of the signal electrode. Each electrode extends in the first direction. Each signal electrode is positioned to provide a signal to two respective waveguides, i.e. each RF transmission line is positioned adjacent to two respective waveguides. The ground electrodes include at least two intermediate ground electrodes positioned between each pair of signal electrodes. Intermediate ground electrodes of different RF transmission lines are separated from each other by channels.
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
A radio frequency, RF, waveguide array. The array comprises a substrate and an electrical RF transmission line array. The substrate comprises a plurality of waveguides, each waveguide being elongate in a first direction. The electrical RF transmission line array is located on a face of the substrate and comprises a plurality of signal electrodes and at least two ground electrodes. Portions of the ground electrodes which are relatively distal from the signal electrodes have reduced height in the direction transverse to the substrate to reduce the amount of material required to produce them.
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
15.
OPTIMISED RF INPUT SECTION FOR COPLANAR TRANSMISSION LINE
A chip comprising a bonding pad region and a transmission section. The bonding pad region has a first impedance, and is configured for electrical connection to an external transmission line. The transmission section extends away from the bonding pad region and has a second impedance. The bonding pad region is configured to enable field confinement and field matching between the bonding pad region and the external transmission line, and the second impedance is not equal to the first impedance.
An RF transition assembly (300) for enabling a radiofrequency transition between an RF transmission layer (301) of an electronic device and a conductor (309) which is electrically connected (317) to the RF transmission layer (301). The conductor (309) extends generally orthogonal to the RF transmission layer (301). The assembly comprises an open coaxial structure (313) located adjacent to an edge of the RF transmission layer (301). The open coaxial structure (313) comprises a cavity (315) extending therethrough for receiving the conductor (309). The cavity (315) comprises an opening facing the edge of the RF transmission layer (301) so as to direct electromagnetic radiation towards the RF transmission layer (301).
The invention relates to optical modulation devices and, in particular, monolithically integrated optical modulation devices. Disclosed herein is a monolithically integrated optical modulation device (200) that comprises: an input optical port (210); an output optical port (215); and an optical waveguide for guiding light from the input optical port to the output optical port. A portion of the optical waveguide is split into at least two branches. The waveguide is configured to cause a net 180° change in direction of the light while guiding said light from the input optical port to the output optical port such that the input optical port and the output optical port are positioned on a first edge of the device. At least some of the net 180° change in direction is achieved within the branches of the waveguide.
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
An optical communications apparatus comprising a host (100) and an optical module (200) comprising a Mach-Zehnder modulator (202), MZM, wherein the optical module is removably connected to the host via a connection path, the optical communications apparatus comprising: a signal generator (101) at the host, configured to generate a plurality of calibration signals at a plurality of frequencies; a host interface (102) configured to transmit the calibration signals to the optical module via the connection path; a module interface (201) configured to receive the transmitted calibration signals; wherein the MZM is configured to use the calibration signals to modulate a laser light source (206) and biased to a point at which average output power is proportional to the output modulated signal; an optical detector configured to measure an average magnitude of an output of the MZM when each of the calibration signals is used to modulate the laser light source; one of a host calibration unit (103) and a module calibration unit (203), configured to determine a magnitude response of the connection path based on the measured average magnitudes and magnitudes of the respective calibration signals, and further configured to determine a pre-emphasis characteristic based on the magnitude response, the pre-emphasis characteristic for application to signals transmitted by the optical transmitter in use.
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
H04B 10/588 - Compensation for non-linear transmitter output in external modulation systems
19.
ELECTRONICAL COMPENSATION OF AN INTERLEAVER TRANSFER FUNCTION FOR OPTICAL MULTIPLE CARRIER TRANSMISSION
There is described a transmitter device for transmitting an optical signal in the form of a plurality of subcarrier channels having different wavelengths. The device comprises first and second optical carrier emitters for emitting light in first and second subcarriers at first and second frequencies or polarisations respectively. First and second modulators are provided for modulating the first and second subcarriers with first and second modulation signals. An interleaver is provided for interleaving the first and second modulated subcarriers into the optical signal. First and second digital signal processing units are configured to pre-emphasise the first and second modulation signals to compensate for a wavelength-dependent power transfer function of the interleaver.
A Mach-Zehnder modulator for modulating optical signals, and comprising: a plurality of modulating waveguide sections; at least one bias electrode in electrical communication with at least one modulating waveguide section and configured to apply at least one electrical bias signal to one or more of the modulating waveguide sections; and an output optical combiner comprising a plurality of inputs and a plurality of outputs, wherein the plurality of inputs of the combiner are in optical communication with output sides of the plurality of modulating waveguide sections, and wherein a plurality of the outputs of the combiner are monitor outputs.
G02F 1/01 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
A monolithically integrated, tunable semiconductor laser with an optical waveguide, comprising a laser chip having epitaxial layers on a substrate and having first and second reflectors bounding an optical gain section and a passive section, wherein at least one of the reflectors is a distributed Bragg reflector section comprising a grating and configured to have a tunable reflection spectrum, wherein the laser is provided with a common earth electrode that is configured to be electrically grounded in use, wherein control electrodes are provided on the optical waveguide in at least the optical gain section and the at least one distributed Bragg reflector section, wherein the passive section is provided with a passive section electrode that electrically contacts the opposite side of the optical waveguide from the substrate, the passive section is configured not to be drivable by an electrical control signal, and no grating is present within the passive section, and wherein the passive section is a grounded passive section in which the passive section electrode is configured to be electrically grounded in use and electrically contacts the passive section, and wherein the passive section electrode and the common earth electrode electrically contact opposite sides of the optical waveguide.
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
H01S 5/0687 - Stabilising the frequency of the laser
H01S 5/12 - Construction or shape of the optical resonator the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
Methods and apparatus for use in coherent transmission and reception of optical data signals. An integrated optics block (100) for use in a coherent optical transmitter comprising: a beam splitter (102) configured to split an input light signal into first and second input light signals, to output the first input light signal for use in an optical transmitter chip and to output the second input light signal for use as a local oscillator signal; a polarisation combiner (104) configured to combine first and second received modulated light signals to form an output; and a polarisation rotator (106) configured to rotate the polarisation of the second modulated light signal such that it is substantially orthogonal to the polarisation of the first modulated light signal prior to combining.
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
An assembly includes an etalon assembly for dynamically locking a frequency of an optical beam to a set frequency, the etalon assembly being external to a laser source assembly that outputs the optical beam. The etalon assembly includes an etalon that receives the optical beam and generates via interference effects a transmission beam, the etalon having a thermal tuning range greater than one half of a free spectral range of the etalon. The etalon assembly also includes an etalon heater mounted to the etalon such that the etalon heater is configured to adjust the temperature of the etalon. The assembly includes a controller configured to retrieve calibration data based on the set frequency, calculate a set temperature for the etalon using a thermal tuning algorithm and the calibration data, and control the etalon heater such that the etalon has a temperature equal to the calculated set temperature.
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/13 - Stabilisation of laser output parameters, e.g. frequency or amplitude
H01S 3/091 - Processes or apparatus for excitation, e.g. pumping using optical pumping
H01S 3/08 - Construction or shape of optical resonators or components thereof
There is disclosed an electronic assembly comprising an electronic device mounted on a carrier and configured to operate within a predetermined range of temperatures. A temperature sensor is thermally coupled to the device for monitoring the temperature of the device. A heater is located in or on the carrier proximate to the electronic device for heating the electronic device. A control system is operatively connected to the temperature sensor and the heater so as to prevent the temperature of the device, when in use, dropping below the predetermined range of temperatures.
A semiconductor distributed Bragg reflector laser configured for single longitudinal mode operation, having an optical waveguide comprising an optical gain section, a first reflector being a first distributed Bragg reflector (DBR) section comprising a grating configured to produce a reflection spectrum having one or more first reflective peaks, and a second reflector, wherein the first DBR section is configured to compensate for thermal chirp that is induced inhomogeneously along the length of the DBR section, in use.
H01S 5/026 - Monolithically integrated components, e.g. waveguides, monitoring photo-detectors or drivers
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
H01S 5/10 - Construction or shape of the optical resonator
The invention relates to a folded Mach-Zehnder modulator. The modulator may comprise a beam splitter configured to split an input light beam into a plurality of light beams. The modulator may comprise a plurality of Mach-Zehnder devices configured to receive one or more of the plurality of light beams. The modulator may comprise a U-turn section configured to receive light beams from the Mach-Zehnder devices and to change the direction of the light beams by substantially 180 degrees. The modulator may comprise a polarisation management section configured to combine light beams received from the U-turn section and to output a polarisation multiplexed phase modulated light beam.
H04B 10/556 - Digital modulation, e.g. differential phase shift keying [DPSK] or frequency shift keying [FSK]
G02F 1/21 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference
The invention relates to an optoelectronic assembly. The optoelectronic assembly comprises one or more optoelectronic components and a housing. The housing comprises an outer wall electrically connected to the one or more optoelectronic elements. The housing is configured to provide an electrical interface between the one or more optoelectronic components and an external electronic device. The electrical connection between the outer wall and the one or more optoelectronic components comprises an electrically conductive element. The electrically conductive element is supported on a dielectric material, such that the dielectric material provides structural support to the electrically conductive element between the one or more optoelectronic components and the outer wall.
An optical switching device with a switch-and-select architecture uses a single multi-port optical channel router, such as a wavelength selective switch, as a bidirectional switching device. The optical switching device includes the multi-port optical channel router and optical circulators coupled to the input/output ports of the multi-port optical channel router. The optical circulators couple one or more output ports and one or more input ports of the optical switching device to the input/output ports of the optical channel router so that the optical channel router provides symmetric, bi-directional switching at an optical network node.
A light detector measures optical power of light incident thereon. Using a beam steering device that is rotatable about two orthogonal axes, wavelength components of different channels are scanned onto the light detector in accordance with programmable parameters. The programmable parameters specify the light detector to which the wavelength components are directed, the order the wavelength components are monitored by the light detector, and the time duration over which each of the wavelength components is monitored by the light detector.
An optical module with a cooling system provides enhanced heat removal using one or more passive cooling devices. Such passive cooling devices include a protrusion through the housing of the optical module that thermally couples a heat-generating component in the optical module to a heat-sink module; a PGS material configured to form wetted contact with adjacent surfaces and therefore provide greater thermal conductivity; and one or more heat pipes configured to thermally couple a heat-generating component in the optical module to a remote heat-sink.
A monolithically integrated, tunable semiconductor laser with an optical waveguide, comprising epitaxial layers on a substrate and having first and second reflectors bounding an optical gain section and a non-driven region, wherein at least one of the reflectors is a distributed Bragg reflector section configured to have a tunable reflection spectrum, wherein control electrodes are provided to at least the optical gain section, and the distributed Bragg reflector section, and wherein the non-driven region has a length of at least 100μm, is without an electrical contact directly contacting onto the epitaxially grown side of the non- driven region, and the non-driven region is without a reflective Bragg grating within the epitaxial layers of the non-driven region.
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
H01S 5/10 - Construction or shape of the optical resonator
A widely tunable multi-mode semiconductor laser containing only two electrically active sections, being an optical gain section and a tunable distributed Bragg reflector section adapted to reflect at a plurality of wavelengths, wherein the gain section is bounded by the tunable distributed Bragg reflector section and a broadband facet reflector, and wherein the tunable distributed Bragg reflector section comprises a plurality of discrete segments capable of being selectively tuned, wherein the reflection spectra of one or more segments of the tunable distributed Bragg reflector section can be tuned lower in wavelength to reflect with the reflection spectrum of a further segment of the tunable distributed Bragg reflector section to provide a wavelength range of enhanced reflectivity. An optical transmitter comprising a light source that is such a widely tunable multi-mode semiconductor laser.
H01S 5/12 - Construction or shape of the optical resonator the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
H01S 5/10 - Construction or shape of the optical resonator
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
33.
EMBEDDED OPTICAL TIME DOMAIN REFLECTOMETER FOR OPTICALLY AMPLIFIED LINKS
Fiber-optic communications systems are provided for optical communications networks. Fiber-optic communications links may be provided that use spans of transmission fiber to carry optical data signals on wavelength-division-multiplexing channels at different wavelengths between nodes. An apparatus and method are disclosed to use one optical light source per node to perform OTDR and LCV to satisfy safety concerns and accelerate the verification of the integrity of optical fiber links, before the application of high Raman laser powered light sources to a fiber link. A system using only one receiver per node is also disclosed.
The present invention discloses an optical fibre (20) for coupling to an optical source (18) which includes a core (22) and a tip portion (36). The core (22) is for receiving light directed from the optical source along an optical axis; wherein the core is expanded near one end of the optical fibre, and the expanded core (24) having a diameter larger than other portions of the core that are not expanded. The tip portion (36) is on the end of the optical fibre, wherein the tip portion further includes an endmost face (26), the endmost face being non-perpendicular to the optical axis. A coupling system including such an optical fibre and a method of fabricating a coupling device for the optical fibre are also disclosed. The optical fibre as provided by the present invention not only enables high coupling efficiency with different laser mode sizes, but also reduces the back reflected laser from the optical fibre which may otherwise damage the laser semiconductor chip.
There is described a high speed vertical-cavity surface-emitting laser (VCSEL) comprising a substrate and first and second distributed Bragg reflectors (DBRs) disposed on the substrate, each comprising a stack of layers of alternating refractive index. A resonant cavity is disposed between the DBRs and an active region disposed in the resonant cavity. The resonant cavity is formed of material having low refractive index and has an optical thickness in a direction perpendicular to the substrate of ½λ, where λ is the wavelength of light emitted by the VCSEL.
H01S 5/10 - Construction or shape of the optical resonator
H01S 5/183 - Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
H01S 5/062 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
09 - Scientific and electric apparatus and instruments
42 - Scientific, technological and industrial services, research and design
Goods & Services
(1) Optical and opto-electronic equipment, namely transponders, switching apparatus, optical interferometers, optical attenuators, lenses, mirrors, receivers, filters, detectors, polarizers, all for use in telecommunications networks and data centres; high-bandwidth fiber optical components for data and telecommunication, namely detector modules, switching modules, add/drop modules, fiber optic transponders, gain modules and passive optics modules, circuit boards, fiber optic coupling apparatus, custom designed optical chips, custom designed semiconductor chips, all for use in for use in telecommunications networks and data centres.
(2) Optical communications and data networking hardware, namely high-bandwidth optical hardware used for fiber optic transmission for use in telecommunications networks and data centres; firmware and software for use in operating all of the aforesaid goods as well as operating semiconductor manufacturing machines, and structural and replacement parts for all of the aforesaid goods.
(3) Optical and opto-electronic equipment namely transceivers for use in telecommunications networks and data centres; fiber optical components for data and telecommunication namely high-bandwidth fiber optic transmitters and receivers for use in telecommunications networks and data centres, high-bandwidth fiber optic transceivers for use in telecommunications networks and data centres.
(4) Lasers and integrated lasers for use in telecommunications networks and data centres; integrated optical circuits for use in telecommunications networks and data centres; fiber optical components for data and telecommunication namely laser diode modules and integrated optics modules for use in telecommunications networks and data centres.
(5) Optical and opto-electronic equipment namely modulators for use in telecommunications networks and data centres; fiber optical components for data and telecommunication namely modulator modules for use in telecommunications networks and data centres. (1) Custom design of optical communications equipment, components, modules and subsystems for use in telecommunications networks and data centres; technical support services, namely providing technical advice related to the design, implementation, and use of optical communications equipment and professional services related to the design of optical communications equipment for use in telecommunications networks and data centres.
37.
AN OPTICAL SYSTEM AND A METHOD FOR IMPROVING AN OPTICAL SYSTEM
Disclosed is an optical system and a method for improving the optical system. The optical system comprises a plurality of semiconductor laser emitters (501, 503), a coupling optic (CL), and one or more transparent plates (T1, T2, T3). Each of the plurality of semiconductor laser emitters (501, 503) is operatively coupled to a fast axis collimating optic and a slow axis collimating optic for collimating a beam emitted by the semiconductor laser emitter, so that the beams emitted by the plurality of semiconductor laser emitters can be substantially parallel beams (B1, B2, B3). The coupling optic (CL) couples the substantially parallel beams (B1, B2, B3) into a fiber (F). The one or more transparent plates (T 1, T2, T3) are so arranged as to obtain a walk-off for at least one of the substantially parallel beams (Bl J32J33) before they arrive at the coupling optic (CL), so that the total width of the substantially parallel beams (B1, B2, B3) arriving at the coupling optic (CL) can be reduced.
The present invention, provides a method and apparatus for phase aligning two optical signals within an optical transmitter to each other (and, in some embodiments, to a pulse carved optical signal) using integrated complementary taps and a dither signal. The phase of a first signal may be intentionally offset relative to the phase of a second signal. Based on the offset, a correction factor may be calculated. The correction factor may be used to shift the phase of the first signal and/or the second signal in order to generally align the signals. This procedure may be automatically performed in a feedback loop to cause the signals to come into alignment and maintain the alignment of the signals during operation of the transmitter.
A voltage-tuned optical filter that is low cost and simple to fabricate uses cascaded etalon modules, each module comprising a liquid crystal etalon, such as a Fabry-Perot etalon, having a relatively small Free Spectral Range (FSR). At least two of the modules are provided with a voltage control to enable Vernier tuning control. For a given overall scan, the voltage-tuned optical filter may operate with reduced voltage ranges for each liquid crystal etalon.
An optical switching device has multiple input ports and multiple output ports and is capable of switching a wavelength component from any of the input ports to any of the output ports. The optical switching device is configured with beam steering arrays that are controlled to provide the switching from any of the input ports to any of the output ports. The beam steering arrays may be microelectromechanical (MEMS) mirror arrays or liquid-crystal on silicon (LCOS) panels. In addition, an array of beam-polarizing liquid-crystal elements provides wavelength-independent attenuation.
A light source package is disclosed for a Raman amplifier node having a primary optical fibre for carrying an optical signal and a secondary optical fibre for carrying the optical signal when the signal is rerouted from the primary optical fibre. The light source package includes a primary light source for emitting light into the primary optical fibre when the optical signal is carried by the primary optical fibre to induce Raman gain of the optical signal, and a secondary light source for emitting light into the secondary optical fibre when the optical signal is carried by the secondary optical fibre to induce Raman gain of the optical signal.
In a high power, i.e. 100W and more, semiconductor laser module, used e.g. in opto-electronics as pump laser modules or in laser machining or medical applications, the laser power is launched into a glass fiber which transports the optical power to a desired location. It is difficult to focus the full laser power into the fiber core's end (8). Any misalignment results in stray energy heating up the fiber and its cladding, often resulting in catastrophic failure of the affected module. The invention concerns a robust and cost-effective design to manage and dissipate the heat generated by absorbing uncontrolled un-coupled and de-coupled stray light or radiation by providing a structure of a transparent ferrule (6) holding the fiber core (2) with its cladding (12), this ferrule (6) being fixed to a heat-dissipating component of the module by a transparent adhesive (20), whereby core (2), cladding (12), adhesive (20), and fer rule (6) each have a predetermined refractive index, chosen such that stray radiation is directed into the heat-dissipating component (5). A reflector (13) at the inner end of the ferrule (6), i.e. opposite the laser and preferably funnel-shaped, diverts any remaining stray radiation also towards the heat-dissipating component (5). This combination of features minimizes or avoids catastrophic damage such as melt-down or ignition.
An assembly is provided for multiplexing light having a plurality of wavelengths and polarised states so as to produce an output of generally unpolarised light having at least two components with different wavelengths. The assembly comprises a plurality of polarisation multiplexers and a selective polarisation rotation device configured to rotate the polarisation of light at a first wavelength through a first controlled angle and to rotate light of a second wavelength through a second controlled angle.
A tunable external cavity laser for use as a pump laser in an optical amplifier such as a Raman amplifier or erbium doped fibre amplifier comprising a semiconductor gain device (12) operable to provide light amplification, a diffraction grating (18) for selecting the wavelength of operation of the laser and a MEMs actuator for changing the selected wavelength. A plurality of gain devices can be coupled together to improve the bandwidth or gain of the optical amplifier.
H01S 3/081 - Construction or shape of optical resonators or components thereof comprising three or more reflectors
H01S 3/094 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
H01S 3/1055 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity one of the reflectors being constituted by a diffraction grating
An adjustable array includes a plurality of optical devices. Each adjustable array device has an optical light output therefrom and is configured whereby the corresponding optical lights of the plurality of optical devices have a predefined nonequivalent relationship relative to one another with respect to an output parameter. In response to a drive signal, the plurality of optical devices are further configured to adjust the corresponding optical lights with respect to the output parameter while substantially maintaining the predefined nonequivalent relationship.
H04B 10/80 - Optical aspects relating to the use of optical transmission for specific applications, not provided for in groups , e.g. optical power feeding or optical transmission through water
46.
PHOTODIODE ARRAY WITH ALGORITHM-BASED CROSSTALK REDUCTION
A photodiode (PD) array accurately measures incident optical power on each of the PDs in the array by eliminating the effect of crosstalk between the individual PDs. Crosstalk within the PD array is removed by measuring the current generated by each PD in the array and generating a corrected optical power value for each PD that is based on the measured current for each PD and on coupling coefficients associated with other PDs in the array. The coupling coefficients are determined during a previous calibration procedure.
A pump unit (402) for a Raman amplifier (400) including an optical fibre (401) carrying an optical signal (420) is disclosed. The pump unit includes at least two light sources (411, 412, 431, 432) for emitting light at different wavelengths into the fibre to induce Raman gain of the optical signal passing along the fibre, and a controller (409) for providing pulses to each of the light sources to control when they do and do not emit light. The controller is configured to control the width of the pulses to control the total power of the light emitted into the fibre.
H01S 3/102 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the active medium, e.g. by controlling the processes or apparatus for excitation
H01S 3/094 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
H01S 3/30 - Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
An optical amplifier system is disclosed, comprising an optical fibre (301) for carrying an optical signal and a light source (107, 314) for emitting light into the fibre to induce Raman gain of the optical signal passing along the fibre. An optical signal to noise ratio (OSNR) monitor (109) is coupled to the fibre for measuring OSNR of theoptical signal. A controller (108) is coupled to the light source (107) and the OSNR monitor for controlling the Raman gain by setting the power of the light source based on the measured OSNR. In order to improve the OSNR, co- and counter - propagating pump light is provided for the Raman amplification in the fibre (301).
H01S 3/094 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/102 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the active medium, e.g. by controlling the processes or apparatus for excitation
H01S 3/13 - Stabilisation of laser output parameters, e.g. frequency or amplitude
H01S 3/30 - Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
H04B 10/291 - Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
A laser-locker assembly comprising an optoelectronic chip, an off-chip wavelength discriminator (104), an off -chip photodetector (106), and a laser controller (108). The optoelectronic chip comprises a laser (110), an optical waveguide (114), and an on-chip photodetector (116). The laser has a transmission end for optically coupling to an optical modulator and an opposite end. The optical waveguide and the on-chip photodetector are optically coupled to receive light emitted from the opposite end. The optical waveguide optically connects to a chip outlet provided at a facet of the optoelectronic chip. The wavelength discriminator and off -chip photodetector are optically coupled to receive light from the chip outlet in use. The laser controller is adapted to receive respective first and second electrical signals from the on-chip to control an operating wavelength of the laser in correspondence with the first and second electrical signals in use.
H01S 5/0687 - Stabilising the frequency of the laser
H01S 5/026 - Monolithically integrated components, e.g. waveguides, monitoring photo-detectors or drivers
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
A Mach-Zehnder interferometer 200 comprising an optical splitter 201 having at least one input 203R and at least two outputs 204L, 204R, an optical recombiner 202 having at least two inputs 205L, 205R and at least one output 206R and a pair of interferometer arms 207L, 207R. Each of the arms couples an output of the splitter to an input of the recombiner. The arms are configured such that each of the outputs of the splitter is coupled to an opposite side input of the recombiner so as to compensate for phase imbalance of light propagating through the arms. The interferometer is configured such that the splitter and the recombiner operate in cross-state to compensate for split ratio offset errors in the splitter and recombiner.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
G02B 6/293 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
51.
METHOD AND APPARATUS FOR CONTROLLING DISTRIBUTED ATTENUATION IN AN OPTICAL FIBRE
A variable optical attenuator comprising an optical fibre and a means for applying controllable longitudinally varying external stress to at least part of the length of the fibre so as to attenuate light passing through the fibre.
A photonic assembly is described. The assembly comprises a substrate. An optical modulator (100) in or on the substrate has an output port coupled to an output waveguide (106) mounted in or on the substrate. A spiller waveguide (107, 108) is mounted in or on the substrate. The spiller waveguide (107, 108) has an input end (109, 110) physically separated from but proximate to the output waveguide (106) so as to collect light spilt from the output port or output waveguide (106). The modulator (106) may be a MZI modulator.
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
53.
OPTICAL WAVEGUIDE ARRANGEMENTS COMPRISING AN AUXILIARY WAVEGUIDE - LIKE STRUCTURE
An optical waveguide arrangement is provided which comprises an active ridge waveguide structure12 formed by etching of a semiconductor substrate 1, 2, 3. There is also provided an auxiliary waveguide-like structure 8 formed on the substrate adjacent the active ridge waveguide structure12 to control the etched profile of the active waveguide structure. The arrangement of the auxiliary structure 8 on the substrate controls the etched profile over the cross-section of the active waveguide structure12 and along the length of the active waveguide structure12. Advantageously, this arrangement reduces or eliminates the disadvantages associated with etch-process induced asymmetries in the shape of closely spaced waveguides.
G02B 6/136 - Integrated optical circuits characterised by the manufacturing method by etching
G02B 6/28 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
Described are tunable multiport optical filters that filter systems with many optical channels in a convenient and cost-effective manner. The tunable multiport optical filters of the invention are simple in design and have few optical components. The basic elements are a dispersion element and a rotating reflector. With properly arranged arrays of input and output optical fibers, individual wavelength components from a selected input beam are spatially separated and steered by the rotating reflector to selected output locations. The optical properties from the selected components may be measured by one or more photodetectors. The filters are also useful for selecting and routing optical signals.
A demodulator for a polarisation diverse optical signal comprises a polarising beam splitter arranged to spilt an incoming optical signal into a first beam having a first polarisation state and a second beam having a second polarisation state, an input for a coherent reference beam, and at least two balanced detectors, respectively configured to detect the difference between the first beam and the reference beam and the second beam and the reference beam. A path balancer is also provided to enable the first and second beams to have substantially equal optical lengths.
A semiconductor laser device is described comprising an optical emitter and a wavelength locking mechanism arranged to control the temperature of the optical emitter in order to maintain a desired optical wavelength. Also described is a wavelength locking mechanism for a semiconductor laser and a method for stabilising the wavelength of a semiconductor laser comprising monitoring the wavelength of the laser and controlling the temperature of the laser in order to maintain a desired optical wavelength.
H01S 5/0687 - Stabilising the frequency of the laser
H01S 5/0683 - Stabilisation of laser output parameters by monitoring the optical output parameters
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
There is described a laser assembly for providing light at a switchable output wavelength. The assembly comprises first and second tuneable lasers (101, 201), each configurable to emit light at a laser wavelength chosen from a range of wavelengths. Light is transmitted from the first laser while the second laser is retuned to change the chosen laser wavelength thereof. Each laser comprises one or more thermally sensitive control components for controlling the operation of the laser and an additional component electrode (104, 204) located adjacent to at least one of the one or more control components (103, 203). The laser is configured so that the sum of electrical currents supplied to each control component (103, 203) and its corresponding additional component (104, 204) remains substantially constant in use. Switching from one laser to the other may be realized by monolithically integrated SOA (108, 208) with adjacent dummy SOA (109, 209) to keep the thermal load of the assembly constant and to prevent a thermal drift after wavelength switching.
H01S 5/026 - Monolithically integrated components, e.g. waveguides, monitoring photo-detectors or drivers
H01S 5/0625 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in multi-section lasers
H01S 5/40 - Arrangement of two or more semiconductor lasers, not provided for in groups
H01S 5/06 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
A temperature-tuned dielectric-slab-etalon scanning spectrometer that is low cost and simple to fabricate uses cascaded etalon modules, each module comprising a Fabry-Perot (FP) etalon having a relatively small Free Spectral Range (FSR), with at least two modules provided with a temperature control. According to the invention, the multiple FP modules produce Vernier tuning control. In these devices, the tuning temperature range is typically less than 10°C, and the required slab thickness may be less than 1 mm. This reduces fabrication and material requirements, and results in lower device cost and improved reliability.
G02F 1/03 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels or Kerr effect
An electro-optic device 200 comprising a substrate in which first and second waveguides 202, 203 are formed. The device also comprises first and second electrodes 204, 205 comprising an optically transparent conductive material and including primary portions 204a, 205a overlying the first and second waveguides 202, 203 for electrically biasing the first and second waveguides. The device is configured such that one of the first and second electrodes includes one other portion 204b, 205b arranged alongside the primary portion 204a, 205a of the other of the first and second electrodes. This arrangement improves the electro-optic efficiency of the device without the need for a buffer layer in the electrodes.
G02F 1/035 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels or Kerr effect in an optical waveguide structure
G02F 1/225 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
An optoelectronic device which comprises an opticalwaveguide 100 for modulating light. The device also comprises an electrode102overlying the waveguide100 for electrically biasing the waveguide to effect such modulation. At least a portion 1 of the waveguide underneath the electrode is tapered. This arrangement reduces thermal dissipation density at the front end of the electrode.
G02F 1/025 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction in an optical waveguide structure
An optoelectronic device for generating an optical pulse train comprises a phase modulator (9) for modulating the phase of an optical signal received from a laser (3) in accordance with a clock signal and outputting a phase modulated signal. The device further comprises an all-pass optical filter (10) for receiving the phase modulated signal and modifying the phase modulated signal to produce intensity modulation. Such a device provides higher output peak power compared to a conventional pulse carver.
An optical amplifier system comprises an optical amplifier having an amplifying stage (511, 512) to amplify an optical signal. The amplifier also generates an amplified spontaneous emission (ASE) noise over a band of wavelengths. The system further comprises an optical filtering assembly comprising an ASE flattening filter (AFF) and a comb filter. These filters are provided in combination to substantially attenuate the ASE noise in a continuous inverse relationship to the ASE noise over at least some of the wavelengths and to substantially remove the ASE noise between the channel wavelengths of the band. These effects result in an improved signal to ASE noise ratio (S/ASE) compared to that of a conventional amplifier system in which a filtering assembly comprises none or one of the AFF and the comb filter.
Described are tunable multiport optical filters that filter systems with many optical channels in a convenient and cost-effective manner. The tunable multiport optical filters of the invention are simple in design and have few optical components. The basic elements are a dispersion element and a rotating mirror. With properly arranged arrays of input and output optical fibers, individual wavelength components from a selected input beam are spatially separated and steered by the rotating mirror to selected output locations. The optical properties from the selected components may be measured by one or more photodetectors. The filters are also useful for selecting and routing optical signals.
An enclosure for a laser package the enclosure being configured to receive a laser component within the enclosure, and further configured to receive for a driver integrated circuit (IC) (34) on the exterior of the enclosure, wherein the enclosure comprises first external electrical contacts (52) electrically connected to respective first IC electrical contacts (60), and second IC electrical contacts (62) electrically connected to respective first internal electrical contacts (64), wherein the first and second IC electrical contacts (60, 62) are configured for electrical connection to the driver IC (34). Heat dissipation of the driver IC is improved for the IC being mounted outside of the enclosure.
An optoelectronic device which comprises an optical source (1) for emitting a light beam (6) of a first optical power, and an optical fibre (2) for receiving a light beam of a second optical power different to the first optical power. The device also comprises a first cylindrical lens (4) having a first longitudinal plane, and a second cylindrical lens (5) having a second longitudinal plane transverse to the first longitudinal plane. The focal length of the first lens (4) and the focal length of the second lens (5) are selected to convert the first optical power to the second optical power acceptable to the optical fibre (2). Advantageously the manufacturing of the cylindrical lenses is simple and cost effective.
Optical communications networks rely on optical receivers to demodulate optical signals and convert the demodulated optical signal into an electrical signal. Optical receivers may be associated with one or more characteristics which can be made to vary during a transmission of an optical signal in order to improve the quality of the received signal. The present invention may determine a value for the characteristics based on an amount of optical filtering on a communications link which transmits the signal. The value for the characteristics of the receiver may be determined by observing a characteristic of a detector associated with the receiver, such as a ratio of the average photocurrents of the constructive and destructive ports of the detector. The observed characteristic of the detector may be mapped to a predetermined value for the characteristic of the receiver in a lookup table, which may be queried during operation of the receiver.
H04B 10/00 - Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
An optical amplifier system is provided which comprises first and second optical amplifiers (1, 2) for amplifying optical signals in a fibre optic communications link and a common pump (3) for optically pumping both the first amplifier (1) and the second amplifier (2) to effect such amplification. There is also provided an optical switch (6) for providing an optical path between the pump and the first amplifier in a first switching state and an optical path between the pump and the second amplifier in a second switching state to enable pumping of the first and second amplifiers by the pump sequentially. Advantageously this arrangement provides high accuracy to the outputs (4, 5) of the pump (3) and reduces low power pump noise.
H01S 3/102 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the active medium, e.g. by controlling the processes or apparatus for excitation
H04B 10/294 - Signal power control in a multiwavelength system, e.g. gain equalisation
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
68.
WAVELENGTH DIVISION MULTIPLEXED SYSTEMS WITH OPTICAL PERFORMANCE MONITORS
The specification describes optical performance monitors which are simplified by coupling single tunable optical filters to multiple channels being monitored. Optical measurements for more than one channel may be made simultaneously. The optical system architecture is preferably an optical performance monitor for a WDM system. In a system designed according to the invention n channels may be monitored using n photodetectors, n optical splitters, but only n/2 tunable optical filters. Additional system simplification may be obtained using optical switching elements coupled to the optical splitters.
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
The present application describes methods and systems that improve the optical signal to noise ratio performance of an optical network without the need to vary the free spectral range associated with a differential interferometer. This is achieved by varying an electrical bandwidth of an electronic device associated with the receiver. For example, the electrical bandwidth may vary in inverse proportion to the combined effective optical bandwidth of the transmission line carrying the optical signal. The techniques described herein a applicable to a wide variety of modulation formats, including mPSK, DPSK, DmPSK, PDmPSK, mQAM, ODB, and other direct-detection formats. Using the techniques described herein, the optical signal to noise ratio and bit error ratio performance of the optical network is improved without the need to provide costly and complex differential interferometers whose free spectral range is variable.
A semiconductor laser diode comprises a semiconductor body having an n- region and a p-region laterally spaced apart within the semiconductor body. The laser diode is provided with an active region between the n-region and the p-region having a front end and a back end section, an n-metallisation layer located adjacent the n-region and having a first injector for injecting current into the active region, and a p- metallisation layer opposite to the n-metallisation layer and adjacent the p-region and having a second injector for injecting current into the active region. The thickness and/or width of at least one metallisation layer is chosen so as to control the current injection in a part of the active region near at least one end of the active region compared to the current injection in another part of the active region. The width of the at least one metallisation layer is larger than a width of the active region. This arrangement results in substantially uniform current distribution near the front end of the active region. Advantageously, this uniform current density significantly improves the reliability of the laser diode.
A tunable dispersion compensator (TDC) is tuned from a first dispersion setpoint to a second dispersion setpoint while maintaining continuity of the dispersion. The dispersion tuning follows a pre-determined trajectory in the time domain, so that continuity of the optical dispersion across the channel optical bandwidth is maintained while minimizing all other TDC-induced optical impairments during a tuning period.
According to a first aspect of the present invention there is provided an apparatus for performing power equalisation and phase correction of two signals (400). The apparatus comprises a first hybrid coupler (401) configured to operate as a power combiner, and a second hybrid coupler (402) configured to operate as a power divider, wherein the apparatus is configured to provide an output (406) of the first hybrid coupler as an input (407) to the second hybrid coupler.
G02F 1/01 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour
A method of operating a production optical amplifier comprises determining a training data set of amplified spontaneous emission (ASE) values of a training optical amplifier over a plurality of training operating conditions, determining a production data set of ASE values of the production optical amplifier over a plurality of production operating conditions, the plurality of production operating conditions corresponding to a sub-set of the plurality of training operating conditions, determining an adjusted data set of adjusted ASE values produced by extrapolation from the production data set so that the adjusted data set is provided over a plurality of operating conditions corresponding to the plurality of training operating conditions, determining, for each of a plurality of operating conditions, a dynamic ASE tilt factor from the training data set and the adjusted ASE data set so determined, determining a larger data set of ASE values over a wider set of operating conditions than either the training data set or the production data set from the adjusted AS E dataset and the dynamic ASE tilt factor, and compensating the optical output power of the production optical amplifier in correspondence with the larger ASE data set generated from the production data set and the dynamic ASE tilt factor over the plurality of operating conditions, which is preferably a larger set of operating conditions than that of the training data set or production data set. Advantageously a compensating ASE value can be more quickly and cheaply determined by this method compared to those shown in the prior art.
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H04B 10/073 - Arrangements for monitoring or testing transmission systemsArrangements for fault measurement of transmission systems using an out-of-service signal
H01S 3/13 - Stabilisation of laser output parameters, e.g. frequency or amplitude
74.
WAVELENGTH DIVISION MULTIPLEXED SYSTEMS WITH OPTICAL PERFORMANCE MONITORS
The specification describes optical performance monitors which are simplified by coupling single tunable optical filters to multiple channels being monitored. Optical measurements for more than one channel may be made simultaneously. The optical system architecture is preferably an optical performance monitor for a WDM system. In a system designed according to the invention n channels may be monitored using n photodetectors, n optical splitters, but only n/2 tunable optical filters. Additional system simplification may be obtained using optical switching elements coupled to the optical splitters.
G01B 9/00 - Measuring instruments characterised by the use of optical techniques
H04B 10/079 - Arrangements for monitoring or testing transmission systemsArrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
There is described an optoelectronic device having a housing and a chip housed by the housing. At least a portion of the chip protrudes through an aperture in a wall of the housing. There is further provided an optoelectronic module comprising such an optoelectronic device and electronic control circuitry adapted to control the operation of the optoelectronic device.
A multi-port wavelength selective switch includes a one dimensional array of input and output ports. The multi-port wavelength selective switch further includes a wavelength dispersive element configured to receive input optical signals from the input ports, and to disperse wavelength components thereof. Additionally, the multi-port wavelength selective switch includes an array of beam steering devices. Each beam steering device is controllable to a position at which the beam steering device directs a wavelength component of an input optical signal received through a first input port to an output port and directs the same wavelength component of an input optical signal received through a second input port away from all of the output ports.
A laser device having a semiconductor gain element (12) optically coupled to an optical fiber (14) by using an angled anamorphic fiber lens (28) and including a wavelength-selective front reflector (26). The laser device possesses improved output characteristics such as a highly linear laser emission output, even when the amplification section produces a high amount of gain. Such a laser source can also be used in various applications such as pump lasers for fiber amplifiers or frequency doubling systems. The semiconductor gain element (12) has a curved waveguide with the intracavity facet (18) and the inclined fiber lens tip (30) being substantially parallel to prevent wavelength and intensity instabilities of the external cavity LD.
A method of treating a surface for an electronic or optoelectronic component to be bonded with adhesive, and a substrate comprising a ceramic surface for an electronic or optoelectronic component. A coating is applied to the surface that causes a reduction in the surface energy of the surface.
C03C 17/30 - Surface treatment of glass, e.g. of devitrified glass, not in the form of fibres or filaments, by coating with organic material with silicon-containing compounds
C09D 4/00 - Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond
C09J 5/02 - Adhesive processes in generalAdhesive processes not provided for elsewhere, e.g. relating to primers involving pretreatment of the surfaces to be joined
H01L 21/00 - Processes or apparatus specially adapted for the manufacture or treatment of semiconductor or solid-state devices, or of parts thereof
79.
METHOD AND SYSTEM FOR DEPLOYING AN OPTICAL DEMODULATOR ARRANGEMENT IN A COMMUNICATIONS NETWORK
The present application describes methods and systems for use in a communications network. More specifically, a method of deploying an optical demodulator arrangement having at least one interferometer in a network that transmits an optical signal is provided. The optical signal may include one or more on-off-keyed signals and one or more DMPSK signals. In some embodiments, the DMPSK signal is a DQPSK signal. The network may include one or more of fiber spans carrying the signals. The interferometer may have a first optical path and a second optical path and a time delay is formed between the first and second optical paths. The method may involve determining a cross-talk penalty that results from cross-phase modulation between the channels, and determining a time delay value for the interferometer. The time delay value may be determined based at least in part on determined the cross-talk penalty.
A plurality of semiconductor optical devices (12a, 12b) has a common package (200) and common supporting structures (16, 18) and controls. The semiconductor optical devices are typically semiconductor lasers or photodiodes and are designed for operation independently of each other or in a coordinated way. In one embodiment, co- packaged semiconductor lasers may be used individually to drive each of the amplification stages of a multi-stage optical amplifier. The optical fibers (26a, 26b) connecting to the optical devices share a common port (20) and are aligned prior to engagement with the light output/input of the co-packaged semiconductor optical devices.
Described are Gain Flattening Filters (GFFs) implemented using mechanical translating assemblies to move selected thin film Gain Attenuating Filters (GAFs), and combinations of selected GAFs, into or out of the output path from an optical amplifier. The GAFs may be used singly, or in combinations that synthesize many target filter characteristics. The GFF is primarily adapted for WDM systems operating with a wavelength range of approximately 1520 nm to 1620 nm. Several embodiments are shown for effectively combining different GAFs to provide multiple GFF curves.
The specification describes delay line interferometer designs using combinations of basic optical components that are expected to simplify manufacture and reduce costs while still providing precision optical performance. The main operative components of these designs are polarization beam splitters, birefringent crystals, optical delay components, and waveplates. Temperature controllers may be provided for adjusting the delay of the optical delay components.
An optical wavelength monitor photodiode integrated on a wafer and/or an optical device and coupled to optical components thereof provides wavelength measurement. The optical wavelength monitor includes a photodiode configured to output a signal that is representative of a wavelength of the light. An additional photodiode may be included in the optical wavelength monitor, each photodiode differing from the other in operating characteristics. The monitor may be used in testing the optical device while in wafer form and when the optical device has been cleaved from the wafer at the bar level. Testing/monitoring of the optical device may also be performed during use, for example, to control the wavelength of a laser such as a tunable laser.
H01S 5/026 - Monolithically integrated components, e.g. waveguides, monitoring photo-detectors or drivers
H01S 5/0687 - Stabilising the frequency of the laser
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
84.
LIQUID CRYSTAL OPTICAL SWITCH CONFIGURED TO REDUCE POLARIZATION DEPENDENT LOSS
An optical device has the structure to perform switching and attenuation of an optical beam with reduced polarization dependent loss (PDL). The optical device includes a birefringent displacer and two liquid crystal (LC) structures. The first LC structure is used to condition s-polarized components of the optical beam and the second LC structure is used to condition p-polarized components of the optical beam. Each LC structure has a separate control electrode so that the s-polarized components of the optical beam and the p-polarized components of the optical beam can be conditioned differently and in such a manner that reduces PDL. The optical device may be configured for processing multiple input light beams, such as the multiple wavelength channels de-multiplexed from a wavelength division multiplexed (WDM) optical signal.
Sacrificial optical test structures are constructed upon a wafer (100) of pre-cleaved optical chips (10) for testing the optical functions of the pre-cleaved optical chips (10). The sacrificial optical structures are disabled upon the cleaving the optical chips (10) from the wafer (100) and the cleaved optical chips (10) can be used for their desired end functions. The test structures may remain on the cleaved optical chips (10) or they may be discarded.
In a ridge waveguide serial interferometer mode conversion is induced by a first mode conversion section, a phase difference between modes is introduced by propagation over a length of waveguide and optical interference is produced following further mode conversion induced in a second mode conversion section. The first mode conversion section has a first radius of curvature, which is equal to a second radius of curvature of the second mode conversion section. The ridge waveguide interferometer advantageously provides an equal phase dependency as a function of temperature.
G02B 6/28 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
G02B 6/12 - Light guidesStructural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
An Mach-Zehnder interferometer (500) incorporates a tunable multimode interference coupler comprising a tunable MMI coupler (504) with a tuning electrode (524) on a surfcae of a tunable MMI region (516) and an electrically- insulating region provided within the tunable MMI region. The MMI region is tuned in response to detection of a photocurrent measured by an integrated photodetector section (510, 512). Such a tunable MZO is particularly advantageous in enabling a controlled split ratio of an optical splitter.
G02B 6/28 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
An optical device performs both switching and attenuation of an optical beam, where the beam has an arbitrary combination of s-polarized and p-polarized components. The optical device includes a birefringent displacer, a liquid crystal (LC) beam-polarizing structure having six subpixels organized in a first polarization group and a second polarization group, a half-wave plate positioned for polarization control of the second polarization group, and a polarization separating and rotating assembly. The structure of the LC beam-polarizing structure allows for 1x2 switching and attenuation control with a single control signal. The optical device may be configured for processing multiple input light beams, such as the multiple wavelength channels de-multiplexed from a wavelength division multiplexed (WDM) optical signal.
Optical devices are disclosed consisting of optical chips (planar lightwave circuits) which have optically symmetric or matching designs and properties and optical components which create asymmetry in the optical devices. The devices find application in detection in coherent and non-coherent optical communications systems.
An optical device is configured to perform both switching and attenuation of an optical beam in response to a single control signal. The optical device includes a liquid-crystal-based beam-polarizing element having polarization-conditioning regions that are controlled using a common electrode. The first polarization-conditioning region conditions the polarization of the input beam in order to separate the input beam into a primary component and a residual component. The second and third polarization-conditioning regions change the polarization of the primary component and the residual component, respectively. The primary component is directed to an output port after it has been attenuated based on its polarization state. The residual component, after passing through the third polarization-conditioning region, has its intensity further reduced based on its polarization state.
A laser module comprising a laser device attached to a heat sink that is configured to provide a relatively low thermal resistance for thermal management of the laser device, and an aggregate coefficient of thermal expansion (CTE) that is substantially matched to the CTE of the laser device for reducing stress caused by thermal cycles. The heat sink includes a shell made out of a first material, and a core situated within the shell and made out of a second material distinct from the first material of the shell. By properly selecting the first and second materials, configuring the thickness of the shell directly under the location to which the laser device will be attached with respect to the thickness of the core, the desired effective or aggregate CTE and thermal resistance of the heat sink may be achieved.
Optical signal bands having different bandwidths are selectively directed along different optical paths. Some optical signal bands are directed along more than one optical path. Also, a group of optical signal bands having different bandwidths may be directed along a selected optical path.
G02F 1/1347 - Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
09 - Scientific and electric apparatus and instruments
38 - Telecommunications services
42 - Scientific, technological and industrial services, research and design
Goods & Services
(1) Lasers and integrated lasers not for medical use; integrated optical circuits; optical equipment, in the nature of sub-systems and modules comprised of optical lasers, filters, detectors, receivers, transmitters, modulators, choppers, optic mounts, prism mounts, top mounts, fiber aligners, multi-axis stages, translation stages, beam pick-offs, polarizing beamsplitter cubes, neutral density filters, aspheric lenses, ultraviolet excimer mirrors, dielectric mirrors, IR sensor cards, metal mirrors, neutral density mirrors, optic polarizers, sheet polarizers, and variable wave plates; fiber optic transceivers; fiber optic switching apparatus; wavelength selective switches; fiber optic coupling apparatus; custom designed optical chips; opto-electronic devices, namely, phase and amplitude modulators, modulator drivers, and high-voltage amplifiers; optical waveguides; optical communication systems comprised of electronic and fiber-optics hardware components; sensors, namely, high-speed photodetectors; gyroscopes and distance measuring apparatus, namely, test and measurement non-medical tunable lasers; laser diodes, non-medical lasers, namely, tunable lasers; industrial lasers, communications lasers, lasers for use in printers; optical modulators, optical amplifiers; erbium doped fiber amplifiers (EDFAs), optical receivers, transmitters, transponders and transceivers; field effect transistors (FETs), monolithic microwave integrated circuits (MMICs); receivers, namely, optical and electrical receivers; optical modulators, amplifiers, and repeaters, multiplexers, demultiplexers, add-drop multiplexers, fixed and reconfigurable optical add/drop modules, photodiodes, p-i-n diodes, avalanche photodiodes, optical filters, filters in the form of color sequencing wheels, thin-film filters for optical devices; microwave RF devices for transmitting and receiving radio waves, opto-mechanical devices, namely, optical choppers. optical laboratory equipment, namely, beam pick-offs, polarizing beamsplitter cubes, neutral-density filters, aspheric lenses, UV excimer and dielectric mirrors, polarizers and wave plates. optical spectrometers, optical spectroscopy equipment in the nature of non-medical lasers, namely, fixed-wavelength violet, blue, green and red lasers; computers and computer software for use in operating all of the above, as well as operating semiconductor manufacturing machines, precision mechanical machines, precision positions machines, and medical and non-medical lasers; precision mechanical devices, namely, optical amplifiers and pump diodes for optical communications networks, transmitters, transceivers, receivers and thin- film filters for use with optical networks; high power laser diodes for solid state and fiber laser pumping, material process and biotechnology applications, and photonics tools, optics, optical filters and detectors; optical interferometers; optical attenuators; optical temperature sensors, optical chemical sensors; biological sensors; advanced fiber-optic components and subsystem, namely, dense wavelength division multiplexers, dense wavelength wavelength division de-multiplexers and tunable chromatic dispersion compensators, for use in photonic network applications, namely, the transmission of multiple signals and compensation of chromatic dispersion through and in optical fiber communications systems; Optical communications and data networking hardware, namely, optical hardware used for fiber optic transmission; structural and replacement parts for all of the aforesaid goods (1) Custom design of optical communications equipment, components, modules and subsystems; technical support services, namely, providing technical advice related to the design, implementation, and use of optical communications equipment and professional services related to the design of optical communications equipment
09 - Scientific and electric apparatus and instruments
Goods & Services
Lasers and integrated lasers not for medical use; integrated optical circuits; optical equipment, in the nature of sub-systems and modules comprised of optical lasers, filters, detectors, receivers, transmitters, modulators, choppers, optic mounts, prism mounts, top mounts, fiber aligners, multi-axis stages, translation stages, beam pick-offs, polarizing beam splitter cubes, neutral density filters, aspheric lenses, ultraviolet excimer mirrors, dielectric mirrors, IR sensor cards, metal mirrors, neutral density mirrors, optic polarizers, sheet polarizers, and variable wave plates; fiber optic transceivers; fiber optic switching apparatus; wavelength selective switches; fiber optic coupling apparatus; custom designed optical chips; opto-electronic devices, namely, phase and amplitude modulators, modulator drivers, and high-voltage amplifiers; optical waveguides; optical communication systems comprised of electronic and fiber-optics hardware components; sensors, namely high-speed photo detectors; gyroscopes and distance measuring apparatus, namely, test and measurement non-medical tunable lasers; laser diodes, non-medical lasers, namely tunable lasers; industrial lasers, communications lasers, lasers for use in printers; optical modulators, optical amplifiers; erbium doped fiber amplifiers (EDFAs), optical receivers, transmitters, transponders and transceivers, field effect transistors (FETs), monolithic microwave integrated circuits (MMICs); receivers, namely, optical and electrical receivers; optical modulators, amplifiers, and repeaters, multiplexers, de-multiplexers, add-drop multiplexers, fixed and reconfigurable optical add/drop modules, photodiodes, p-i-n diodes, avalanche photodiodes, optical filters, filters in the form of color sequencing wheels, thin-film filters for optical devices; microwave RF devices for transmitting and receiving radio waves, opto-mechanical devices, namely, optical choppers; optical laboratory equipment, namely, beam pick-offs, polarizing beam splitter cubes, neutral-density filters, aspheric lenses, UV excimer and dielectric mirrors, polarizers and wave plates, optical spectrometers, optical spectroscopy equipment in the nature of non-medical lasers namely fixed-wavelength violet, blue, green and red lasers; computers and computer software for use in operating all of the above, as well as operating semiconductor manufacturing machines, precision mechanical devices, namely, optical amplifiers and pump diodes for optical communications networks, transmitters, transceivers, receivers and thin-film filters for use with optical networks; high power laser diodes for solid state and fiber laser pumping, material process and biotechnology applications, and photonics tools, optics, optical filters and detectors; optical interferometers; optical attenuators; optical temperature sensors, optical chemical sensors; biological sensors; advanced fiber-optic components and subsystem, namely, dense wavelength division multiplexers, dense wavelength division de-multiplexers and tunable chromatic dispersion compensators, for use in photonic network applications, namely, the transmission of multiple signals and compensation of chromatic dispersion through and in optical fiber communications systems; optical communications and data networking hardware, namely optical hardware used for fiber optic transmission; structural and replacement parts for all of the aforesaid goods.
An optical receiver includes a demodulator having a delay interferometer comprising an optical input that receives a phase modulated optical signal from a bandwidth limited transmission system. The delay interferometer has a free spectral range that is larger than a symbol rate of the phase modulated optical signal by an amount that improves receiver performance. The receiver also includes a differential detector having a first and a second photodetector. The first photodetector is optically coupled to the constructive optical output of the delay interferometer. The second photodetector is optically coupled to the destructive optical output of the delay interferometer. The differential detector combines a first electrical detection signal generated by the first photodetector and a second electrical detection signal generated by the second photodetector to generate an electrical reception signal.
An optical communication device such as a transmitter or receiver has a control loop for controlling relative phase of two related optical signals based on signal peak intensity. An optical transmitter measures the signal peak intensity of a combined optical signal representing two data channels to adjust relative phase as desired. An optical receiver measures the signal peak intensity of combined electrical signals, single electrical signals or single optical signals to adjust relative phase as desired. Signal peak intensity is minimized or maximized by adjusting the relative phase, depending upon the modulation configuration used. The feedback control provides a consistent and robust control to stabilize the optical communication device in the presence of variables such as temperature changes, aging and manufacturing tolerances .
